CGSC Strain#: 8176
Strain Designation: VS101      Source of Strain: V.A. Stupina
Sex: F- Chromosomal Markers: Δ(gpt-proA)62, lacY1, tsx-29, glnX44(AS), galK2(Oc), λ^-, lacZp-topA76(L5F C662H), zci-2234::cat, cysB38, Rac-0, hisG4(Oc), rfbC1, kdgK51, xylA5, mtl-1, argE3(Oc), thiE1
Strain Comments:

• This strain will grow at 37-42 C in LB + 15 ug/ml chloramphenicol, but for growth at 30 C it requires 1 mM IPTG.
• glnX44(AS)-- Mutation is a C to T transition at nucleotide 34 (3rd position of the anticodon)
• galK2(Oc)-- is a GAA(glu) to TAA(ochre) mutation, residue 134. Oller et al.1993. Apparently non-suppressible, since all revertants found were at the ochre site.
• lacZp-topA76(L5F C662H)-- replaces promoter topAp of allele topA78(G65N W79S substitutions in TopoI) with lacZp, resulting in an IPTG requirement for expression.
• lacZp-topA76(L5F C662H)-- : poor growth at 30C in absence of IPTG; At 42C, TopoI level is low and more negative supercoiling is observed, but the strain grows if it is topB⁺.
• zci-2234::cat-- is an insertion of cam at a unique SphI site in region 5' (counterclockwise) of the topA gene
• Δ(gpt-proA)62 was formerly called proA2
• galK2(Oc) was formerly called gal₂
• glnX44(AS) was formerly called su⁺_II
• glnX44(AS) was formerly called supE44
• glnX44(AS) was formerly called glnV44
• rfbC1 was formerly called rfbD1
• thiE1 was formerly called thi-1
• = chloramphenicol resistant
• AS = amber(UAG) suppressor
• L5F C662H = amino acid changes in TopoI
• Oc = ochre(UAA) mutation

References:

• Stupina, V.A., J.C. Wang 2005. Viability of Escherichia coli topA mutants lacking DNA topoisomerase I. J.Biol.Chem. 280:355-360